To find the system load use the following perl snippet :

1) System load of last one minute :

my $system_load = exec('uptime | awk -F "load average: " \'{ print $2 }\' | cut -d, -f1');
my $system_load = qx('uptime | awk -F "load average: " \'{ print $2 }\' | cut -d, -f1');

2) System load of last 5 minutes :

my $system_load = exec('uptime | awk -F "load average: " \'{ print $2 }\' | cut -d, -f2');
my $system_load = qx('uptime | awk -F "load average: " \'{ print $2 }\' | cut -d, -f2');

3) System load of last 15 minutes :

my $system_load = exec('uptime | awk -F "load average: " \'{ print $2 }\' | cut -d, -f3');
my $system_load = qx('uptime | awk -F "load average: " \'{ print $2 }\' | cut -d, -f3');